Display list of templates [BBcode] separated into "Core" and "3rd Party"

[sozzled]

This is a wish list request.

In a similar manner to how Components, Modules and Plugins are displayed in the BBcode, separated into "Core" and "3rd Party", do the same for Templates.

Not urgent and does not affect the immediate/imminent release of v1.6.0.

In the longer term, the separation of Templates as "Core" vs. "3rd Party" may assist with the way that BBcode generation (as well as improving execution of the FPA PHP script) is handled.